From: Nick Piggin <npiggin@suse.de>
To: levon@movementarian.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: [patch] oprofile: fix memory ordering
Date: Thu, 23 Oct 2008 16:25:54 +0200 [thread overview]
Message-ID: <20081023142554.GA22805@wotan.suse.de> (raw)
Regular bitops don't work as locks on all architectures.
Also: can use non-atomic unlock as no concurrent stores to the word.
Signed-off-by: Nick Piggin <npiggin@suse.de>
---
Index: linux-2.6/drivers/oprofile/event_buffer.c
===================================================================
--- linux-2.6.orig/drivers/oprofile/event_buffer.c
+++ linux-2.6/drivers/oprofile/event_buffer.c
@@ -105,7 +105,7 @@ static int event_buffer_open(struct inod
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- if (test_and_set_bit(0, &buffer_opened))
+ if (test_and_set_bit_lock(0, &buffer_opened))
return -EBUSY;
/* Register as a user of dcookies
@@ -129,7 +129,7 @@ static int event_buffer_open(struct inod
fail:
dcookie_unregister(file->private_data);
out:
- clear_bit(0, &buffer_opened);
+ __clear_bit_unlock(0, &buffer_opened);
return err;
}
@@ -141,7 +141,7 @@ static int event_buffer_release(struct i
dcookie_unregister(file->private_data);
buffer_pos = 0;
atomic_set(&buffer_ready, 0);
- clear_bit(0, &buffer_opened);
+ __clear_bit_unlock(0, &buffer_opened);
return 0;
}
next reply other threads:[~2008-10-23 14:26 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-23 14:25 Nick Piggin [this message]
2008-10-27 18:27 ` Robert Richter
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